Restore Legacy buttons

Rectangle, transparent etc. now work using a presenter, too.
Make message box send a message to the card, not background.

Msg is now separate object to the scripts in it, which it probably shouldn't be. Need to make it return the card for "me" etc.
Fixed "rectangle" property. Properties now have a type.
Track Forge HEAD.
Added "create [new] button [<name>]" command